The present invention relates to a recording/reproducing apparatus and, more particularly, to an improvement of a cue recording system for a tape recorder.
It is convenient to use cuing to find a particular recorded segment on a magnetic tape. For example, a cue signal is recorded at the beginning of a speech of a specific person A. When this cue signal is detected in the playback mode, the speech of person A can be quickly searched and reproduced.
The following two systems are known to record/reproduce the cue signal of the type described above.
(1) System using a monaural (one channel) record/playback head
According to this system, a low-frequency component of an audio signal is cut off or removed, and a cue signal having the same frequency as that of the low-frequency component is superposed on the audio signal. Such a composite signal is recorded on a single recording track. In the playback mode, a filter having a sharp cutoff slope (e.g., -18 to -24 dB/oct) is required to separate the cue signal from the audio signal having voice frequency components. A filter of this type is expensive. Further, since the audio signal is separated by a high-pass filter from the cue signal, the low-frequency response of the audio signal is degraded.
(2) System using a stereo (two-channel) record/playback head
According to this system, the audio signal is recorded on the first recording track, and the cue signal is recorded on the second recording track. In the playback mode, the audio signal is reproduced from the first track, while the cue signal is reproduced from the second track. In this case, unlike the system using the monaural head, said expensive filter is not necessary. Thus, degradation of the low-frequency response of the audio signal can be avoided, and the frequency of the cue signal may be freely selected. However, the recording track width in the system using the stereo head becomes less than half of that used in the system using the monaural head. For this reason, an output level of the stereo head system becomes lower than that of the monaural head system by 3 dB or more. Therefore, an S/N ratio of the reproduced audio signal in the stereo head system is degraded.